Chapter 14: Corballis, M. C. The evolution of language: From hand

Chapter 14: Corballis, M. C. The evolution of language: From
hand to mouth (pp. 403-429)
Infamous incident: 1866 The Linguistic Society
of Paris banned all discussion of the evolution of
Logic: Language was believed to be uniquely
human, no evidence of it could therefore be
deduced from animal studies nor the fossil
record so all “theories” of language evolution
were mere speculation, not science.
Contention remains even today
Bickerton and Chomsky – language is
evolutionarily “discontinuous.”
Pinker and Bloom – language as gradual product
of evolution
Evolution of Language
• Recent findings have largely vindicated an
evolutionary approach
• Vervet monkey alarm calls – animal signals as
referential (symbolic?)
• Kanzi studies
Evolution of Language
• Faculties of Language (Hauser,
Fitch & Chomsky, 2002).
• Broad sense: communicative
capacities shared with animals
(reference, simple syntax, etc.)
• Narrow sense: recursion
• Recursion: The ability to
“embed” concepts are routines
within each other.
• “This is the cat that worried the
rat that ate the malt that lay in
the house that Jack built.”
Ape Language Studies
• Washoe
Nim Chimpsky
• Fouts/Gardners
Francine Patterson
Herb Terrace
Kanzi: The talking Bonobo
Sue Savage-Rumbaugh
Lexigram symbol language
Simple syntax
Spontaneous acquisition
90% utterances:
Ape language studies
• Lesson: At best this is
• Protolanguage: language without
complex syntax, recursion,
past/future tense (“grammar”)
• Is protolanguage a precursor to
“real” language or indicative of a
general problem solving ability? –
combining symbols to get a reward
similar to Sultan combining crates
to get food.
Proto to “real” language?
• Evidence of protolanguage to “real” language
• Pidgin to creole studies
• Evidence from ontogeny
Hominin Evolution
• Australopiths: 4.5-1.3mybp bipedal apes, no evidence of requisite
cognitive abilities for language
• First stone tools – Oldowan Industry 2.5mybp; increased motor
control but not cognition
• Acheulean Industry and emergence of Homo erectus (1.71.8mybp); more human than ape
Brain Evolution
• Major increase in brain size
around 2mybp with emergence
of Homo
• Corresponds roughly to
deactivation of MYH16 gene
which controls jaw muscle
growth (2.4mybp)
• Corresponds to evidence of
mutation in brain regulator gene
CMAH, releasing a constraint on
brain size (2.1 mybp).
• Direct selection pressure for
these may have been living in
more open territory requiring
increased group sizes and
Life History
• Life history as critical to language evolution
• Slower post-natal growth period may allow developmental time for
language acquisition.
• Later Homo species (antecessor; heidelbergensis, 800-500kybp)
marks a transition to a more “human-like” pattern of prolonged
post-natal development and increased altriciality in infancy.
• Elfman’s computer simulation studies: “growth” factor required
with degraded “global” inputs for machine to learn grammatical
Language from Gesture
• Speech should not be consider totality of language;
facial expressions, bodily gestures play important
semantic role in linguistic communication
• Sign language shows all important defining features of
• Primates have far greater voluntary control over limb
movements than vocalizations.
Fossil Evidence: Late emergence of articulate speech
• Evolution of hypoglossal canal: pathway for the
hypoglossal nerve (from medulla through hgc to
tongue) which is critical for control of tongue. Early
hominins had hgc in great ape range, not until
Neandertals and Homo sapiens is hgc in modern range.
Fossil evidence
• Thoracic spinal
pathway: important
for control of
breathing. Again,
not in range until
• Erectus vertebrae
from Asia (l) and
Fossil evidence
• Shortening of the sphenoid: central bone of
cranial base from which face grows. Flattened
face may play important role in speech
articulation by improving symmetry of vocal
tract. Not present in Neandertals, only unique
to Homo sapiens branch.
Fossil evidence
• Neocranial globularity: unique to Homo
sapiens; roundness of skull that allows for
relative increases in frontal/temporal region of
brain (Broca; Wernike areas).
Speech as gesture
• Speech as gestural system,
not acoustic one
• Coarticulation problem:
Phonemes exist in the
mind, not in acoustic
• Articulatory phonology:
Speech as fundamentally a
set of articulatory gestures
from mouth, tongue, face,
and body.
Mirror Neurons: connecting perception and production
• Role of mirror neurons: neurons in
premotor cortex that respond not
just to action but to watching an
action. Neural link between
perception and production of
action. Mirror neurons located in
area F5 of monkey brain which
appears to be analogous to Broca’s
area in human brain – close
connection between
perception/control of motor
movements and evolution of
FOXP2: Gene for articulation?
• Role of the FOXP2 gene: may be important for speech
articulation. Important mutation in FOXP2 appears to
have arisen sometime between 100,000 – 10,000 ybp.
• Possibility that “click” languages found in some Africa
traditional societies and (extinct) aboriginal Australian
represent a way of adding sound to facial gesture prior
to FOXP2 mutation.
• Advantages of speech over gesture-based language:
Frees hands for tool use and manufacture
May allow for greater working memory capacity and
therefore more complex expressions
Less attentionally demanding
• Evolutionary scenario:
2mybp: emergence of more complex grammar, associated
with bigger brains (protolanguage)
100,000 move from proto to real language with FOXP2
mutation, extended infant/childhood maturation period